The present invention relates to the art of color proofing, and in particular, to an improved lamination envelope used in the method of preparing a pre-press proof, such as by the use of pressure and heat to laminate media together.
Pre-press proofing is a procedure that is used primarily by the printing industry for creating representative images of printed material. In the printing industry pre-press color proofs are used to check for color balance, control parameters and other important image quality requirements, without the cost and time that is required to actually produce printing plates, set up a printing press and produce an example of a representative image, which would result in higher costs and a loss of profits that would ultimately be passed on to the customer.
To create a pre-press proof first an original image is separated into individual color separations or digital files. The original image is scanned and separated into the three subtractive primaries and black. Typically a color scanner is used to create the color separations or digital files and in some instances, more than four color separations or digital files are used. Although there are several ways used in the printing industry to create a pre-press proof from the color separations or digital files they are generally one of three types. The first method being a color overlay system that employs the representative image on a separate base for each color, which are then overlaid to create a pre-press proof. The second, a single integral sheet process in which the separate colors for the representative image is transferred one at a time by lamination onto a single base. Third, a digital method in which the representative image is produced directly onto a receiver stock, or onto an intermediate sheet then transferred by lamination onto a receiver stock from digital files.
The representative image to be laminated can be created on, but is not limited to, a commercially available Kodak image processing apparatus, depicted in commonly assigned U.S. Pat. No. 5,268,708, which describes an image processing apparatus having half-tone color imaging capabilities. The above-mentioned image processing apparatus is arranged to form a representative image onto a sheet of thermal print media in which colorant from a sheet of colorant donor material is transferred to the thermal print media, by applying a sufficient amount of thermal energy to the colorant donor sheet material to form the representative image. The image processing apparatus is comprised generally of a material supply assembly, a lathe bed scanning subsystem. The scanning subsystem includes: a lathe bed scanning frame, translation drive, translation stage member, printhead, imaging drum, and media exit transports.
The operation of the image processing apparatus comprises of metering a length of the thermal print media (in roll form) from the material supply assembly. The thermal print media is then measured and cut into sheet form of the required length and transported to the imaging drum, registered, wrapped around, and secured onto the imaging drum. Next, a length of colorant donor material (in roll form) is also metered out of the material supply assembly, then measured and cut into sheet form of the required length. It is then transported to the imaging drum and wrapped around the imaging drum utilizing a load roller which is described in detail, in commonly assigned U.S. Pat. No. 5,268,708, such that it is superposed in the desired registration with respect to the thermal print media (which has already been secured to the imaging drum).
After the colorant donor sheet material is secured to the periphery of the imaging drum the scanning subsystem or write engine provides the imaging function. This image function is accomplished by retaining the thermal print media and the colorant donor sheet material on the imaging drum while it is rotated past the printhead. The translation drive traverses the printhead and translation stage member axially along the axis of the imaging drum, in coordinated motion with the rotating imaging drum. These movements combine to produce the representative image on the thermal print media.
Once the representative image has been formed on the thermal print media, the colorant donor sheet material is then removed from the imaging drum. This is accomplished without disturbing the thermal print media that is beneath it. The colorant donor sheet material is then transported out of the image processing apparatus by means of the material exit transport. Additional colorant donor sheet materials featuring other desired colorants are sequentially superimposed with the thermal print media on the imaging drum and then imaged onto the thermal print media as previously mentioned, until the representative image is completed on the thermal print media. The representative image formed thereon is then unloaded from the imaging drum and transported by the receiver sheet material exit transport to an exit tray in the exterior of the image processing apparatus.
After a representative image has been formed on the thermal print media as previously described it is transferred to a receiver stock such that the pre-press proof is representative of an image intended to be printed on a printing press. A Kodak laminator as described in U.S. Pat. No. 5,478,434 can be used to bond or laminate the representative image as a part of a pre-press proofing system. As additional references U.S. Pat. No. 5,203,942 describes a Kodak laminator that employs a lamination/de-lamination system as applied to a drum laminator and pending U.S. patent application Ser. No. 09/676,877, filed Sep. 29, 2000, describes a Kodak laminator that employs endless belts incorporated into the lamination apparatus. For the purpose of this patent application the laminator described in U.S. patent application Ser. No. 09/676,877 will be used. It should be noted that the present invention described in this disclosure is not limited to a Kodak laminator or type of laminator referenced above.
The receiver stock can be sheet-fed press printing stock, specially coated paper stock, or previously laminated stock. In this latter case a sheet of pre-laminate, which has a pre-laminate support layer consisting of a suitable base material, optionally coated with a releasing material, and a thermal print layer, is placed on top of a receiver sheet, which is also called receiver stock in the industry. This construction of multiple layers is a lamination sandwich, which is fed into the laminator. Once the lamination sandwich exits the laminator the pre-laminate support layer is peeled away from the now pre-laminated receiver stock. Any of the laminators referred to above can be used to affect the transfer of the pre-laminate receiving layer to the receiver stock.
Although the above described lamination method works well for most materials and for both laser thermal and inkjet pre-press proofs. There exists a need for improving the life of the lamination envelope and the quality of the laminated pre-press proof such as minimizing image ripple and also expanding the variety of materials, which the thermal print media will laminate to.
The present invention involves a method for forming an improved lamination envelope for use in forming a pre-press proof which comprises laminating at least one surface of a lamination envelope with a pre-laminate sheet comprising a first thermoplastic layer and a first support layer having a first release layer and first support base, forming a lamination sandwich. The first support layer from the lamination sandwich is removed forming a pre-lamination envelope. A stiffener sheet is laminated to the pre-lamination envelope forming an improved lamination envelope.
In another embodiment of the invention a method for using an improved lamination envelope for forming a pre-press proof comprises creating an imaged receiver sheet with an image formed by an inkjet printer, laser printer, or any other printing method known in the art. A second thermoplastic layer and a second support layer having a second release layer, aluminized layer and a second support base is created. The imaged receiver sheet and a receiver stock is inserted into said improved lamination envelope forming an image lamination packet. The image lamination packet is passed through a laminator, forming an imaged lamination sandwich within the image lamination packet. The imaged lamination sandwich is then removed from the improved lamination envelope and the second support layer is removed from the imaged lamination sandwich forming a pre-press proof.
In yet another embodiment of the invention a method for using an improved lamination envelope for forming a pre-press proof comprises inserting a receiver stock and a pre-laminate sheet comprising a first thermoplastic layer and a first support layer having a first release layer and first support base into an improved lamination envelope forming a pre-lamination lamination packet. The pre-lamination lamination packet is passed through a laminator forming a pre-lamination sandwich within the lamination packet. The pre-lamination sandwich is removed from the improved lamination envelope. The first support layer is removed forming a pre-laminated receiver stock. Creating an imaged receiver sheet with an image formed by an inkjet printer, laser printer, or any other printing method known in the art is created. A second thermoplastic layer and a second support layer having a second release layer, aluminized layer and a second support base are inserted. The imaged receiver sheet and a pre-laminated receiver stock are inserted into the improved lamination envelope forming an image lamination packet. The image lamination packet passes through a laminator, forming an imaged lamination sandwich within the image lamination packet. The imaged lamination sandwich is then removed from the improved lamination envelope and the second support layer is removed from the imaged lamination sandwich forming a pre-press proof.
The above described methods can be used to form a pre-press proof with a resolution of between about 1000 and 4000 dpi, although in the most preferred embodiment, the resolution is between 1200 and 3600 dpi.
The method forming an improved lamination envelope for laminating a pre-press proof can be modified so that the first support layer 145 consists of a support base, a second release layer, or just support base.
In still another embodiment of present invention the stiffener sheet can be made from a metal, a plastic sheet or a plurality of plastic sheets, card stock or combinations there of. In the most preferred embodiment, the material is a plastic.
In yet another embodiment of the present invention the second support layer can consist of only two layers, a support base and a release layer or just support base.
In yet another embodiment of the present invention only stiffener sheet be laminated to a lamination envelope to form an improved lamination envelope.
It is contemplated that the first thermoplastic layer and the second thermoplastic layer used in this invention has a thickness between 1 and 75 microns. It is also contemplated that the method of making the improved lamination envelope can be with a belted laminator.
It is within the scope of the invention that the image on the imaged receiver sheet can be either a monochrome image or a multi colored image. It is also contemplated to be within the scope of the invention to use an imaged receiver sheet, which uses an image generated by an inkjet printing method.